SUMMER FINAL EXAM BIO

List characteristics associated with the process of science

Hypothesis, design, experiment, data, conclusion

Describe the steps of the scientific method

Observation, question, hypothesis, predictions, experiment, data collection, data analysis, conclusion, publish

Factors to consider in experimental design

• Independent variable: Amount of fertilizer

• Dependent variable: Plant height

• Controlled variables: Plant type, soil, water, sunlight, pot size

• Control group: No fertilizer

• Experimental group: Receives fertilizer

• Sample size: 20 plants per group

• Replication: Repeat the experiment several times

• Randomization: Randomly assign plants to each group

• Population-bias: Testing a new medicine using only college students and assuming it works the same for everyone

  Subject-bias: Someone exercises harder because they know they're in a fitness study

  Investigator-bias: A scientist gives more encouragement to one group because they believe that group will do better

Scientific theory

Comprehensive explanation for a natural phenomenon; typically supported with multiple lines of evidence. A well-tested explanation supported by lots of evidence from many experiments.

Hypothesis

Tentative, falsifiable explanation for one or more fact observations; may be incorporated into theories. An educated guess that can be tested

Fact

A repeatable observation that everyone can agree on. Something that has been observed and confirmed to be true.

Limitations to scientific inquiry

Experimental evidence may have multiple

interactions.

• Misinterpretation

• Filing drawer syndrome- failure to share

negative results

• Data image manipulation

• Fraud violations

• Ethics violations

• Pseudoscience

• Cherry picking data

• Biases

• Scientific myths (example: vaccines,

GMOs)

• Manipulation/misinterpretation by the

public

Why is chemistry important to understanding biology

Chemistry is everywhere! All life is made of chemical substances and all substances are made of atoms.

Structure of atoms

Protons, neutrons, electrons

Elements that make up the mass of all living organisms

CHNOPS = Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur.

How is the periodic table related to atomic structure

Elements are arranged by

atomic number in the periodic

table.

• Atomic number = # of

protons

• Atomic mass = # of protons

and neutrons

Compare and contrast ion and isotope

• Ion = Different number of electrons → different charge. An atom that has gained or lost electrons

• Isotope = Different number of neutrons → different mass. An atom that has a different number of neutrons.

Compare and contrast atomic number, atomic mass, and atomic weight

• Atomic Number = Protons

• Atomic Mass (Mass Number) = Protons + Neutrons

• Atomic Weight = Average mass of all atoms of an element

Compare and contrast a chemical reaction and a nuclear reaction

Chemical Reaction

• Atoms rearrange their electrons to form new substances.

• No new elements are created.

• Example: Burning wood or rusting iron.

Nuclear Reaction

• The nucleus changes, changing the atom itself.

• New elements can be formed.

• Example: Radioactive decay or nuclear fission.

What they have in common:

• Both involve atoms.

• Both can release or absorb energy.

• Both produce new products.

Chemical Reaction

Atoms rearrange their electrons to form new substances.

No new elements are created.

Example: Burning wood or rusting iron.

Nuclear Reaction

• The nucleus changes, changing the atom itself.

• New elements can be formed.

• Example: Radioactive decay or nuclear fission.

Compare and contrast the types of chemical bonds and atomic interactions that lead to the formation

of molecules

Covalent bonds

• Share electrons.

• Strongest bonds in biological molecules.

• Hold atoms together within molecules.

Ionic bonds

• Transfer electrons.

• Positive and negative ions attract each other.

• Can break apart in water.

Hydrogen bonds

• No electrons are shared or transferred.

• Weak attraction between molecules (or parts of large molecules).

• Important for water's properties and DNA.

Covalent bonds

• Share electrons.

• Strongest bonds in biological molecules.

• Hold atoms together within molecules.

Ionic bonds

• Transfer electrons.

• Positive and negative ions attract each other.

• Can break apart in water.

Hydrogen bonds

• No electrons are shared or transferred.

• Weak attraction between molecules (or parts of large molecules).

• Important for water's properties and DNA.

Explain the concept of electronegativity and how it relates to the formation of ionic and covalent

bonds

Electronegativity is how strongly an atom pulls shared electrons toward itself.

• High electronegativity = pulls electrons strongly.

• Low electronegativity = doesn't pull as strongly.

Covalent bond

• Atoms have similar electronegativities.

• They share electrons.

Polar covalent bond

• One atom pulls harder than the other.

• Electrons are shared unequally.

Ionic bond

• One atom has much higher electronegativity.

• It takes an electron completely.

• Electrons are transferred, not shared.

Describe the relationship between the arrangement of the periodic table and electronegativity

Increases from left → right This means the top-right corner has the highest electronegativity

Explain the properties of carbon that make this element the chemical basis of all life

Carbon is the foundation of all living things because it can form many different molecules.

Forms carbohydrates, Forms lipids, Forms proteins, Forms nucleic acids (DNA & RNA)

Describe the variety and chemical characteristics of common functional groups of organic compounds

cation vs anion

CATS are always PAWsitive, aNions are Negative

Amino

–NH₂ Basic; accepts H⁺; found in amino acids

Phosphate

–PO₄ Negative charge; important in ATP and DNA

Dehydration Synthesis vs. Hydrolysis

Dehydration = Remove water = Build

Hydrolysis = Add water = Break apart

Carbohydrates

Structure

• Carbon, hydrogen, oxygen

• Usually a 1:2:1 ratio

Function

• Quick energy

• Energy storage

• Structural support (plants)

Examples

• Glucose

• Starch

• Glycogen

• Cellulose

Lipids

Structure

• Glycerol + fatty acids

• Mostly carbon and hydrogen

• Hydrophobic (water-repelling)

Function

• Long-term energy storage

• Insulation

• Cell membranes

• Hormones

Examples

• Fats

• Oils

• Waxes

• Phospholipids

• Steroids

Proteins

Structure

• Chains of amino acids

Contain:

• Carbon

• Hydrogen

• Oxygen

• Nitrogen

• Sometimes sulfur

Function

• Enzymes

• Build tissues

• Transport molecules

• Immune defense

• Muscle movement

Examples

• Enzymes

• Hemoglobin

• Antibodies

• Keratin

Nucleic Acids

Structure

• Made of nucleotides

Each nucleotide has:

• Sugar

• Phosphate

• Nitrogen base

Function

• Store genetic information

• Instructions for making proteins

Examples

• DNA

• RNA

Monosaccharide

1 sugar Glucose Quick energy

Disaccharide

2 sugars Sucrose and lactose Short-term energy

Polysaccharide

Many sugars Starch, glycogen, cellulose Energy storage or structure

Plant vs. Animal Polysaccharides

Plants = Starch

Animals = Glycogen

Cellulose = Plant cell walls

Proteins

• Monomer = Amino acid

• Polymer = Polypeptide

4 levels = Primary → Secondary → Tertiary → Quaternary

Functions = Enzymes, transport, structure, defense, movement

Nucleic Acids

• Monomer = Nucleotide

• DNA stores information

• RNA helps make proteins

• DNA: A-T, C-G

• RNA: A-U, C-G

• Central dogma: DNA → RNA → Protein

3 Domains of cells

• Bacteria = Prokaryote

• Archaea = Prokaryote

• Eukarya = Eukaryote

Prokaryotes vs. Eukaryotes

Prokaryotes	Eukaryotes
No nucleus	Has a nucleus
No membrane-bound organelles	Has membrane-bound organelles
Small and simple	Larger and more complex
Usually unicellular	Can be unicellular or multicellular
DNA is free in the cytoplasm	DNA is inside the nucleus
Bacteria and Archaea	Plants, animals, fungi, protists

Animal Cells vs. Plant Cells

Animal Cell	Plant Cell
No cell wall but a cleavage	Has a cell wall
No chloroplasts	Has chloroplasts
Small vacuoles	One large central vacuole
Round or irregular shape	Box-like shape
Has centrioles	Usually no centrioles

Describe known characteristics of enzymes

• Made of proteins (most enzymes are proteins).

• Speed up reactions by lowering activation energy.

• Are not used up in the reaction.

• Are specific — each enzyme usually works with one substrate.

• Have an active site where the substrate binds.

• Can be affected by temperature and pH.

• Can become denatured (lose shape and stop working).

Relate activation energy to enzyme activity

Activation energy is the amount of energy needed to start a chemical reaction.

• Enzymes lower activation energy.

• They do not change the amount of energy in the reactants or products.

• They simply make the reaction happen faster.

Compare and contrast different types of enzymatic regulation

• Competitive inhibition: Inhibitor binds the active site.

• Noncompetitive inhibition: Inhibitor binds another site and changes enzyme shape.

• Feedback inhibition: Final product shuts down an earlier enzyme in the pathway.

Describe and classify the various types of cellular transport

Passive Transport (No Energy)

Moves substances from high concentration to low concentration (down the concentration gradient).

A. Simple Diffusion

• Molecules move directly through the membrane.

• No transport proteins needed.

Examples:

• Oxygen (O₂)

• Carbon dioxide (CO₂)

Facilitated Diffusion

• Molecules move from high to low concentration.

• Uses channel or carrier proteins because the molecules are too large or charged.

Examples:

• Glucose

• Ions (Na⁺, K⁺)

Osmosis

Osmosis = diffusion of water

• Water moves across a selectively permeable membrane.

• Water moves from high water concentration (low solute) to low water concentration (high solute).

Active Transport (Uses ATP)

Moves substances from low concentration to high concentration (against the concentration gradient).

Examples:

• Sodium-potassium pump

• Proton pump

Requires ATP.

Exocytosis

Moves materials out of the cell.

Examples:

• Hormones

• Neurotransmitters

Bulk Transport

Moves very large materials.

Endocytosis

Moves materials into the cell.

Examples:

• White blood cells engulf bacteria.

Exocytosis

Moves materials out of the cell.

Examples:

• Hormones

• Neurotransmitters

Bulk Transport

Moves very large materials.

Endocytosis

Moves materials into the cell.

Examples:

• White blood cells engulf bacteria.

Active Transport (Uses ATP)

Moves substances from low concentration to high concentration (against the concentration gradient).

Examples:

• Sodium-potassium pump

• Proton pump

Low → High

Requires ATP.

Osmosis

Osmosis = diffusion of water

• Water moves across a selectively permeable membrane.

• Water moves from high water concentration (low solute) to low water concentration (high solute).

Facilitated Diffusion

• Molecules move from high to low concentration.

• Uses channel or carrier proteins because the molecules are too large or charged.

Examples:

• Glucose

• Ions (Na⁺, K⁺)

High → Low

Passive Transport

Moves substances from high concentration to low concentration (down the concentration gradient).

A. Simple Diffusion

• Molecules move directly through the membrane.

• No transport proteins needed.

• no energy

Examples:

• Oxygen (O₂)

• Carbon dioxide (CO₂)

High → Low

Hypertonic vs. Hypotonic

Solution	Solute Concentration	Free Water	Water Movement
Hypertonic	High	Low	Out of cell
Hypotonic	Low	High	Into cell
Isotonic	Equal	Equal	No net movement

Hypertonic

• More solute outside

• Less free water outside

• Water moves out of the cell.

Result:

• Animal cell shrivels.

• Plant cell becomes plasmolyzed (membrane pulls away from the cell wall).

Memory:
Hypertonic = Higher solute outside = Water leaves the cell.

Hypotonic

• Less solute outside

• More free water outside

• Water moves into the cell.

Result:

• Animal cell swells and may burst (lyse).

• Plant cell becomes turgid, which is healthy because the cell wall prevents bursting.

Memory:
Hypotonic = Lower solute outside = Water enters the cell.

Isotonic

• Equal solute concentration inside and outside.

• Water moves in and out at equal rates.

• No net movement of water.

Result:

• Animal cell stays normal.

• Plant cell becomes flaccid (not fully rigid).